Restrict Sending mails for users

[kool_kid]

hiya

how do we restrict users to send mails to only one domain or no domain at all. I tried by adding this line to /etc/mail/access

Code: Select all

from:mail@domain123.com REJECT

But this stops sending mail to all domains including the local domain i.e "domain123.com".

So how can i setup users to send mails to domain123.com and restrict all other domains.